Known selective call receiving devices, such as a pager, receive paging messages from a message transmission station, such as a base station or the like, of a paging system. For a two-way pager that includes a transmitter for transmitting a response to a given message, it is necessary for the paging system to be able to correlate a message sent to the pager with a response received from the pager. This correlation could be accomplished using a unique identifier associated with each message wherein the unique identifier cannot be reused. However, this would require the paging system to maintain an enormous database of all messages that are sent out to selective call receiving devices for which a response is possible in order to correctly correlate a received responses with the message for which the response was generated.